Study and Analysis of Microstrip Patch Array at 12 GHz for 5G Applications

Study and Analysis of Microstrip Patch Array at 12 GHz for 5G Applications Kirankumar A. Solanki Sankalchand Patel collage of Engineering, Visnagar, Gujarat, India e-mail: solankikiran233@gmail.com Gautam D. Makwana Sankalchand patel collage of engineering, Visnagar, Gujarat, India e-mail: gmakwana@gmail.com Abstract This paper presents a study, analysis of microstrip patch arrays for the 5G application. It is the analysis of a single element, two elements and four elements of microstrip patch designed at 12 GHz. For better impedance matching, corporate feeding network is used in three configurations of an array. Microstrip line and patch are etched on RT Duroid 5880 (dielectric constant of 2.2 and a height of 1.56 mm) substrate material. Corporate feeding is modified and various performance parameters, namely, return loss characteristics, impedance bandwidth, gain, directivity, and radiation patterned are compared with conventional corporate feeding. It is observed an improvement in all performance parameters. From the simulation results of four elements array configuration, it is increased of 120% gain and directivity as compared to a single element configuration. It is also noticed that there is an increase of 478% in impedance bandwidth as compared to a single element configuration. There is decreased of beamwidth in 72% as compared to a single element. Thus, proposed 4-elements microstrip patch array with modified corporate feeding is effective candidate for future 5G applications. Keywords: Microstrip Patch Antenna, Array Antenna, Corporate feed Array, HFSS, 5G, 12 GHz. INTRODUCTION Modern Communication Systems demands the use of antennas that are light weight, easy to excite and perform over a wide frequency range and they should be adaptable with changing system requirements or environmental conditions. This has forced the researcher to innovate on different antenna configurations and feed structures that can operate over a wide frequency range with different polarizations simultaneously. Different types of Array Configurations of microstrip Patch antenna can be used for overcome the constraints of Narrow Bandwidth and Low Gain [1]. In 2009 Design of Corporate fed 2*1 Elements Microstrip Antenna are presented with 20.52% of impedance bandwidth [2]. Advantages of the patch antenna are Low Cost, less weight and less size as well as the High Gain can be achieved by corporate feeding [3]. Typically, main disadvantage of the microstrip patch antenna is its narrow bandwidth. The typical bandwidth of a microstrip patch antenna is around 4% to 7%. Gain of the patch antenna can be increased by using the array. It can be increased up to 3 db by using the double elements [4]. In recent years, demand of the 5G communication is surprisingly increased. Although Demand of the 5G communication is to achieve High Gain and Better Directivity, Enhanced Bandwidth and reduction of size is also considered, also the Low dielectric constant material can be preferred for good Radiation. A thicker substrate will increase the radiated power, reduce conductor loss 1 Page 1-8 MAT Journals 2018. All Rights Reserved

and improve impedance bandwidth. For impedance matching purposes, the offset microstrip line feed are easiest to use since the offset depth controls the input impedance of the antenna. But the feed line radiates and causes pattern and polarization degradation. The coaxial feed reduces spurious feed radiation, but it tends to have a narrow bandwidth [5]. In [6] Microstrip Patch Array Antenna with corporate feeding method is described, which operates on the 4.3 GHz. For single element antenna design different types of feeding method like Inset feeding [7], coaxial probe feeding [8], [9] and quarter wave transformer feeding [10] can be used for better performance. The feed of microstrip antenna affects the radiation characteristics of radiating elements, therefore a care must be taken while deciding the proper feed [11]. In this paper quarter wave transformer feeding method is used for antenna design for a single element, two elements and four elements. Section II Demonstrate the calculation the physical dimensions of Antenna and Section III comprise Procedure of the feed network of a single element, Two elements and Four elements design. Section IV is about to Results and Discussions on the achieved results. Section V gives the conclusion of the presented designs. CALCULATIONS OF PATCH ANTENNA DIMENSIONS: For the designing of Microstrip patch antenna first we have to choose Dielectric substrate and Resonate frequency. Parameters of Antenna can be find out by the equations are described below [12], Find Width of Patch (W) :.(1) Find Effective Dielectric constant (ε reff ),.(2) Where ε reff = Effective Dielectric constant h = Height of Dielectric substrate 1. Find Length extension (ΔL) :. (3) Where ΔL = Length extension 2. Find Actual Length (L) :..(4) Where L = Actual Length Find Dimensions of Ground plane W g and L g : Where W g = Width of ground plane L g = Length of ground plane..(5)..(6) Here desired resonate frequency is 12 GHz, Dielectric constant of substrate (RT Duroid 5880) is 2.2 and Height of the substrate is 1.56mm. As described in (1) to (6) physical parameter of patch antenna at 12 GHz are listed in table 1. Table 1. Patch Dimensions for 12 GHz Antenna W 9.88mm Εreff 1.9526 ΔL 0.7665 mm L 7.36mm Wg 15.88mm Lg 13.36mm Where W = width of patch f r =Resonate frequency c = Free space velocity ε r =Dielectric constant of substrate DESIGN PROCEDURE: The design was carried out using the Ansoft high frequency structure simulator (HFSS) software. The proposed antenna 2 Page 1-8 MAT Journals 2018. All Rights Reserved

consists of three layers: the top is the radiating element, the middle is a substrate which provides mechanical support for the radiating patch elements as well as to maintain the required precision spacing between the patch and its ground plane, and the bottom is the ground plane which provide support and increase the bandwidth of the antenna in order to meet up the design requirements. RT Duroid 5880 (dielectric constant of 2.2 and height of 1.56 mm) is used for better Impedance Bandwidth. Design and analysis of single element: Geometry of single element is shown in the Fig.1. Quarter wave transformer impedance can be found out by,..(9) Where Z q = Quarter Wave transformer impedance R in = Edge impedance, Z c =Characteristic impedance(50 Ω) For proposed design we can get Z q = 86 Ω One can find out the width of the microstrip feedline by these equations:...(10). (11) Fig. 1. Geometry of Single Element antenna at 12 GHz [ W=9.88 mm, L=7.36 mm, W 1 =1.92 mm, L 1 =4.2 mm, W 2 =4.8 mm, L 2 =4.2 mm ] Edge impedance of the antenna can be found out by Design and analysis of two element: Corporate feeding method is chosen to feed the array elements. In that type of configuration two-way power divider is used which divides 50 Ω feedline into a 100 Ω feedline as depicted in Fig.2. Quarter wave transformers(123 Ω) are used to match the 100Ω lines to the edge impedance (151 Ω). Geometry of Two elements array is shown in the Fig.2....(7). (8) Where R in = Edge impedance G e = Transconductance of Patch W = Width of Patch λ 0 = Free space velocity For this antenna we get R in =151 Ω Fig. 2. Geometry of Conventional Two Elements array with corporate feeding at 12 GHz 3 Page 1-8 MAT Journals 2018. All Rights Reserved

After Calculations we get Width of the strip lines for different impedances by equation (10) and (11). For 50 Ω = 4.80 mm For 100 Ω = 1.32 mm For 123 Ω = 0.74 mm The cut slots or curved feed performs the major role in radiation for antenna. It distributes power in each patch adequately. By using the cut slots we have modified the conventional design as shown in Fig.3. Fig. 4. Geometry of Conventional Four Elements array with corporate feeding at 12 GHz After Calculations we get Width of the 70.7 Ω strip line is 2.64 mm by equations (9), (10) and (11). Modified Geometry for the Four element array is shown in Fig.5. Fig. 3. Geometry of Modified Two Elements array with corporate feeding at 12 GHz [ W=9.88 mm, L=7.36 mm, W 1 =0.74 mm, L 1 =4.2 mm, W 2 =1.32 mm, L 2 =4.2 mm, W 3 =4.8 mm, L 3 =9.1 mm ] Design and analysis of Four elements In that configuration two-way power divider is used which divides 50 Ω feedline into a 100 Ω feedline, ant to match with the another 100Ω equally divided feedline, 70.7 Ω quarter wave transformers are used. Another Quarter wave transformers (123 Ω) are used to match the 100 Ω lines to the edge impedance (151 Ω) as depicted in Fig.4. Geometry of four elements is shown in the Fig.4. Fig. 5. Geometry of Modified Four Elements array with corporate feeding at 12 GHz [ W=9.88 mm, L=7.36 mm, W 1 =0.74 mm, L 1 =4.2 mm, W 2 =1.32 mm, L 2 =4.2 mm, W 3 =2.64 mm, L 3 =4.2 mm, W 4 =1.32 mm, L 4 =4.2 mm, W 5 =4.8 mm, L 5 =4.2 mm ] RESULTS AND DISCUSSIONS: Single Element Patch Antenna From Fig.6. single element patch antenna is resonates at 12 GHz and having a return loss of -42dB. Impedance bandwidth is 580 MHz (11.71 GHz 12.29 GHz) and % Bandwidth of 4.83 %. 4 Page 1-8 MAT Journals 2018. All Rights Reserved

modified configured array is better to use than conventional array. Fig. 6. S 11 Parameter for 12 GHz single element antenna Radiation pattern of E-plane and H-plane at 12 GHz are shown in Fig 7. It has broad band and linear radiation pattern. Single element antenna has 5.02 db & 5.07 db gain and directivity respectively. Name Theta Ang Mag m1 0.0000 0.0000 5.0919 m2 0.0000 0.0000-49.7558-90 -60-120 -30-150 Radiation Pattern 1 0 m1 0.00-20.00-40.00 m2-180 -60.00 30 150 60 120 90 Curve Info Freq='11.984GHz' Phi='0deg' Freq='11.984GHz' Phi='90deg' Freq='11.984GHz' Phi='0deg' Freq='11.984GHz' Phi='90deg' HFSSDesign1 Fig. 7. Radiation Pattern of 12 GHz Single Element antenna Two Element Patch Antenna: The cut slots or curved feed performs the major role in radiation for antenna. Here we have shown the comparison of S 11 Parameter between the Conventional Array and Modified Array in Fig.7, which shows the curved feed in modified Array configuration, improves the power spitting in each direction and enhance the radiation characteristics. ANSOFT Fig. 8. Comparison of S 11 parameter for corporate feeding of Conventional and Modified Antenna with corporate feeding for 12 GHz Two Elements array Besides, Main requirement is to E plane separation between two antennas in this type of geometry. It is concluded that for any planner array configuration, optimized antenna characteristics can be obtained depending upon the element spacing. The effect of mutual coupling can be minimized by optimizing the inter element spacing [13]. We have carried out numerical study on E- plane separation between elements (S). For two elements array various S = 0.8λ, λ and 1.5λ are studied and analyzed. Return loss characteristics of these are shown in Fig 6, It is observed that E-plane separation S of 0.8λ has better return loss characteristics (S 11 = -38 db) and resonates at 12 GHz as compared to S= λ and 1.5λ. It is concluded that at 12 GHz, S= 0.8λ is optimized separation between two elements for two element array. Conventional configured antenna resonates at 12 GHz but at return loss of - 20 db where as the Modified array configured antenna resonates at 12 GHz at return loss of -38 db. According to this analyzed result we can concluded that the Fig. 9. Comparison of S 11 parameter for different separations between two elements for Two Elements array 5 Page 1-8 MAT Journals 2018. All Rights Reserved

ANSOFT Journal of Remote Sensing GIS & Technology From Fig.8 and 9 two elements patch array antenna is resonates at 12 GHz and having a return loss of -38 db. Impedance bandwidth is 1.24 GHz (11.26 GHz 12.50 GHz) and % Bandwidth of 10.3 %. It is observed that the bandwidth is increased by 660 MHz (114%) than single element antenna. Radiation pattern of E-plane and H-plane at 12 GHz are shown in Fig 10. It has broad band and linear radiation pattern. Two element array antenna has 5.16 db & 5.29 db gain and directivity respectively. We have carried out numerical study on E- plane separation between elements (S). For two elements array various S = 0.7λ, 0.8λ and 0.9λ are studied and analyzed. Return loss characteristics of these are shown in Fig 6, It is observed that E-plane separation S of 0.9λ has better return loss characteristics (S 11 = -37 db) and resonates at 12 GHz as compared to S= 0.7λ and 0.8λ. It is concluded that at 12 GHz, S= 0.9λ is optimized separation between two elements for four element array. Radiation Pattern 1 HFSSDesign1 m1 0-30 30-4.00 Curve Info Freq='12GHz' Phi='0deg' Name Theta Ang Mag m1 0.0000 0.0000 8.2912 m2 0.0000 0.0000-35.3103-60 -18.00 m2-32.00 60 Freq='12GHz' Phi='90deg' Freq='12GHz' Phi='0deg' -46.00 Freq='12GHz' Phi='90deg' -90 90-120 120-150 -180 Fig. 10. Radiation Pattern of Two Elements array with modified corporate feeding at 12 GHz Four Element Patch Antenna: Same like Two elements array antenna the cut slots or curved feed is perform the major role in radiation for four elements also. Here we have shown the comparison between the result of Antennas Geometry of Conventional and Modified S 11 Parameter in Fig.12. It is observed that from Fig. 12 the result of configuration of Modified antenna array has better return loss characteristic compare to configuration of Conventional antenna array. Fig. 11. Comparison of S 11 parameter for Patch Geometry of Conventional Array and Modified Array with corporate feeding for Four Elements at 12 GHz 150 Fig. 12. Comparison of S 11 parameter for different separations for Four Elements array with modified corporate feeding configuration Fig. 12 shows simulated S parameter of the four elements and it can be seen that it resonates at frequency of 12 GHz, with return loss of -38 db with the Wide bandwidth of 3.35 GHz. It shows that Bandwidth achieved by Four elements antenna is 2.77 GHz (478 %) Higher than single element antenna and 2.11 GHz (174 %) Higher than a two elements patch array antenna. Fig. 13 show that the antenna achieves a gain of 11.39 db and its Directivity is about to 11.51 db. The gain is achieved approximately 6 db (120 %) higher than the single element antenna and 3 db (37 %) Higher than Two elements array antenna. 6 Page 1-8 MAT Journals 2018. All Rights Reserved

Name Theta Ang Mag m1 0.0000 0.0000 11.5113 m2 0.0000 0.0000-43.3392-90 -60-120 -30-150 Radiation Pattern 1 0 m1 0.00-20.00 m2-40.00-180 -60.00 30 150 60 120 90 Curve Info Freq='12GHz' Phi='0deg' Freq='12GHz' Phi='90deg' Freq='12GHz' Phi='0deg' Freq='12GHz' Phi='90deg' HFSSDesign1 Fig.13. Radiation Pattern of Four Elements array with modified corporate feeding at 12 GHz Comparison of Antenna Parameters: Comparison of the S 11 Parameter of all antennas with optimized separation and modified configuration are shown in the Fig. 14. Fig. 14. Return loss characteristics of modified configuration with corporate feeding for three antennas. Table No. 3 Shows the overall comparison of the antennas performance parameters and it shows that Gain as well as the Bandwidth of the antenna increases when increase the antenna elements. ANSOFT From the Table 3 it is observed the improvement in all performance parameters. From the simulation results of four elements array configuration, it is increased of 120 % gain and directivity as compared to single element configuration. It is also noticed that there is increase of 478 % in impedance bandwidth as compared to single element configuration. There is decreased of beamwidth in 72 % as compared to single element. CONCLUSION In presented work Single element antenna, two elements array and four elements array with optimized separation are designed and analyzed. For an array antenna with a number of patch elements are improves Gain, Bandwidth as well as Directivity. Separation between two elements performs the major role in antenna performance. Additionally Cut slots in the feedline can also improve the power radiating capability and improve the performance. It is observed that the Single element antenna achieves the gain of 5.02 db with the Bandwidth of 580 MHz, 2*1 elements array achieves the gain of 8.16 db with the bandwidth of 1.24 GHz, 4*1 elements array has the wide Bandwidth as 3.35 GHz and high gain of 11.29 db. All presented antennas are good competitors for future 5G Communications and can be used for the 5G systems like WLAN, WiMax. Table 3. Comparison of the antennas performance parameters for single element, two elements and four elements Antennas Parameters Single Element Two Elements Four Elements Return loss -42 db -38 db -38 db Gain 5.02 db 8.16 db 11.39 db Directivity 5.07 db 8.29 db 11.51 db Impedance 580 1.24 GHz 3.35 GHz Bandwidth MHz % 4.83 % 10.3 % 27.9 % Bandwidth Beam width 78 48 22 Efficiency 99 % 98 % 99 % REFERENCES 1. H. Errifi, A. Baghdad, A. Badri, and A. Sahel Design and Analysis of Directive Microstrip Patch Array Antennas with Series, Corporate and Series Corporate Feed Network International Journal of Electronics and Electrical Engineering Vol. 3, No. 6. December 2015. 2. Dilip Singh Rawat, Gaurav Singh, and R P Singh Design of a Corporate fed 1*2 Microstrip Array Antenna for X 7 Page 1-8 MAT Journals 2018. All Rights Reserved

Band Application International Journal of Computer Applications (0975 8887) Volume 95 No.5, June 2014. 3. J.D. Kraus, Antenna and wave propagation, McGraw- Hill Companies, Inc. 4. Randy Bancraft, Microstrip and Printed Antenna Design, Prentice- Hall of India Private Limited. 5. Ramesh Garg, Prakash Bhatia and Inder Bahl, Microstrip Antenna Design Handbook Artech House 2001. 6. Mohammad Riyazuddin and j. Ramlal Bharath, Design and Simulation of C-band Microstrip Corporate Feed Array Antenna 2015 13 th International Conference on Electromagnetic Interference and Compatibility (INCEMIC). 7. M. Ramesh and YIP KB, Design Formula for Inset Fed MicrostripPatch Antenna, Journal of Microwaves and Optoelectronics,Vol.3,N.o 3, December 2003. 8. S. E Jasim, M. A. Jusoh, M. H. Mazwir and S. N. S. Mahmud, Finding the Best Feeding Point Location of Patch Antenna Using HFSS ARPN Journal of Engineering and Applied Science, December 2015. 9. TVS Divakar, Dhruba C. Panda, Finding Optimal Feed Location of a Microstrip Patch Antenna using HFSS International Journal of Innovative Research in Electrical, Electronics, Instrumentation and Control Engineering Vol. 2, Issue 10, October 2014. 10. N. Ab Wahab and Wan Norsyafizan W Muhammad, Microstrip Rectangular 4*1 Patch Array Antenna at 2.5 GHz WiMax Application 2010 Second International Conference on Computational Intelligence, Communication System and Networks. 11. K. Parveen Kumar, K. Sanjeeva Rao, T. Sumanth, N. Mohana Rao, R. Anil Kumar, Y. Harish, Effect of Feeding Technique on the Radiation Characteristics of Patch Antenna: Design and Analysis International Journal of Advanced Research in Computer and Communication Engineering Vol. 2, Issue 2, February 2013. 12. Constantine A. Balanis, Antenna Theory Analysis And Design, John Willy And Sons, Inc. 13. Samir Dev Gupta and Amit Singh Design of Microstrip Planar Antenna Array and Study of Effect on Antenna Parameters due to Mutual Coupling in both E and H planes International Journal of Communication Engineering Applications IJCEA, Vol 02, Issue 02; June 2011. 14. A. De, C. K. Chosh and A. K. Bhattacherjee, Design and Performance Analysis of Microstrip Patch Array Antennas with different configurations International Journal of Future Generation Communication and Networking, Vol. 9, No.3 (2016). Pp. 97 110. 15. Yahya S. H. Khraisat, Design of 4 Elements Rectangular Microstrip Patch Antenna with High Gain for 2.4 GHz Applications Modern Applied Science Vol. 6, No. 1; January 2012. 16. Christos G. Christodoulou, Fundamentals of Antennas : Concepts and Application. 17. Hala Elsadek, Microstrip Antennas for Mobile wireless communication system 8 Page 1-8 MAT Journals 2018. All Rights Reserved